1. Field of the Invention
The present invention relates to an internal combustion engine. Especially, the present invention relates to an improvement of an integrated cam bracket (of the internal combustion engine) bearing two rotatable cam shafts.
2. Description of the Related Art
A general DOHC (=Double Over Head Cam shaft) type internal combustion engine has the following constitution. Above a cylinder head, there are provided two cam shafts for driving an intake valve and an exhaust valve. The two cam shafts are rotatably born by means of a plurality of cam brackets. Each of the cam brackets is secured to the cylinder head with a pair of bolts. The above constitution using the plurality of the cam brackets may have a great number of component parts and thereby complicate assembly.
Japanese Patent Unexamined Publication No. Heisei 6(1994)-317110 (=JP6317110) discloses an integrated cam bracket {rocker shaft cap} having a ladder frame constitution in which a plurality of bearing beams {cap parts} bridge across two side frames {beam parts}. A cam shaft is rotatably born with the plurality of the bearing beams {cap parts}.